The field of the invention relates generally to high temperature filter elements, and more particularly to high temperature filter elements that include high temperature polymer retaining straps.
Some known filter elements have pleated filtration media for filtering particulates from a particulate laden fluid stream moving in one direction through the filter element. Some known particulate laden fluid streams include hot gas streams associated with coal-fired boilers, cement kilns, and asphalt plants. Such hot gas streams may have extended periods of time the gas stream temperatures range from approximately 275° F. to 500° F. (approximately 135° C. to 260° C.). Also, filter elements are often subjected to cleaning fluid pulses moving for short periods of time through the filtration media in a direction opposite to the direction that the particulate laden fluid stream moves. Such filter elements are referred to as “pulse pleat” filter elements. In order to prevent the filtration media from excessive movement during exposure to the cleaning fluid pulses, some filter elements have retention straps that encircle portions of the pulse pleat filter element.
Some known retention straps for pulse pleat filter elements are difficult to install onto a filter element and may not remain in the relative axial location that they are initially placed. For example, some known retention straps must be manually wrapped about the filtration media of the filter element. Such retention straps are typically tightened manually and the ends of the retention straps are overlapped. The ends of the retention strap are then adhered or fastened together while a desired tension is manually maintained on the retention strap.
Maintaining the retention straps in a pre-determined relative axial location along the filter element facilitates protecting the filtration media from excessive movement during exposure to the cleaning fluid pulses. This is typically accomplished by the use of known adhesives. However, some of the adhesives used on the retention straps may have shortened life expectancies, particularly at elevated temperatures of about 375° F. to 500° F. (about 190° C. to 260° F.) that are used in some hot gas streams industrial applications